Bracken fern linked to upper digestive lesions in buffalo

A new Brazilian case report suggests water buffalo may not be spared from one of bracken fern’s best-known chronic consequences in cattle: upper digestive tract lesions with neoplastic potential. Writing in the Journal of Veterinary Diagnostic Investigation, researchers described three buffalo with proliferative and ulcerative lesions in the mucosa of the base of the tongue, oropharynx, and esophagus associated with ingestion of Pteridium esculentum subsp. arachnoideum. Based on the available literature surfaced in web searches, this appears to be the first published description of upper digestive tract neoplastic and non-neoplastic lesions linked to bracken fern ingestion in buffalo. (journals.plos.org)

That matters because the cattle precedent is well established, especially in southern Brazil. A large 2018 PLOS One study of 100 cattle cases found that upper digestive tract squamous cell carcinomas in bracken-exposed herds were most often associated with chronic plant ingestion over years, with lesions occurring across the oropharynx, esophagus, and rumen entrance. Earlier Brazilian work likewise documented papillomas, transforming papillomas, and squamous cell carcinomas in cattle from bracken-infested farms, with clinical signs including progressive weight loss, dysphagia, regurgitation, cough, halitosis, diarrhea, and bloat. (journals.plos.org)

The newer buffalo report broadens that clinicopathologic picture to another production species. According to the source abstract, all three buffalo had gross proliferative and ulcerative lesions in the upper digestive tract, specifically at the base of the tongue, oropharynx, and esophagus. Even without the full article text, that anatomic distribution closely mirrors the pattern repeatedly described in cattle naturally exposed to bracken fern in Brazil, supporting the authors’ conclusion that chronic ingestion of Pteridium esculentum subsp. arachnoideum can be associated with both neoplastic and non-neoplastic upper alimentary lesions in buffalo as well. (journals.plos.org)

The toxicologic background also fits. A 2021 Frontiers in Veterinary Science review notes that bracken fern contains illudane glycosides such as ptaquiloside, compounds with mutagenic and immunosuppressive properties that are thought to contribute to malignant transformation. That review also summarizes the long-running question of bovine papillomavirus, especially BPV-4, as a possible cofactor in upper digestive tract carcinogenesis. But more recent Brazilian cattle data complicate that theory: in the 100-case PLOS One series, investigators did not detect papillomavirus DNA in sampled papillomas, and an experimental thesis involving prolonged feeding of P. esculentum subsp. arachnoideum to cattle also reported negative BPV DNA findings. Taken together, the current evidence supports bracken fern itself as a sufficient major risk factor, even if viral cofactors remain under study. (frontiersin.org)

Direct outside commentary on the new buffalo paper was limited in the sources available online, but the surrounding literature offers a clear industry and pathology perspective: in Brazil, chronic bracken exposure is not a niche issue. Retrospective and regional studies describe substantial cattle losses and a recurring burden of upper digestive tract tumors in endemic areas, particularly where pasture management allows persistent fern invasion. That context makes the buffalo report more than an isolated curiosity; it signals that veterinarians working with mixed or neighboring ruminant populations in endemic regions may need to think beyond cattle when investigating chronic dysphagia or oral and esophageal masses. (researchgate.net)

Why it matters: For veterinary professionals, this report could influence both differential diagnosis and herd-level risk assessment. In buffalo from bracken-infested environments, chronic upper alimentary signs, poor body condition, regurgitation, or visible oral lesions may justify earlier consideration of plant-associated neoplasia or pre-neoplastic change, alongside more familiar infectious, traumatic, and obstructive causes. It also reinforces the value of pasture surveillance and plant control, because the cattle literature suggests these are chronic exposure diseases that may develop after years of ingestion and may be advanced by the time clinical signs become obvious. (journals.plos.org)

The report may also matter diagnostically because lesion distribution can guide sampling. In cattle, the base of the tongue, pharynx, epiglottis, esophagus, and rumen entrance have all been implicated, and metastasis can occur in more advanced squamous cell carcinomas. For pathologists and field veterinarians, that means careful necropsy of the entire upper digestive tract and regional lymph nodes remains important in suspect cases, whether the patient is bovine or buffalo. (journals.plos.org)

What to watch: The next step is whether additional case series, retrospective surveys, or molecular studies confirm that buffalo share the same chronic bracken-associated disease spectrum seen in cattle, and whether prevalence, lesion behavior, or viral associations differ by species. (frontiersin.org)